1. Field of the Invention
The present invention relates to barrier envelopes, and more particularly to a barrier envelope for reusable photo-stimulable phosphor imaging plates.
2. Description of the Prior Art
Modern digital dental imaging systems utilize reusable photo-stimulable phosphor (PSP) imaging plates compared to traditional x-ray film. The photo-stimulable phosphor imaging plate enclosed within a barrier envelope is positioned within a patient""s oral cavity for subsequent exposure to radiation. After exposure, the encapsulated imaging plate is removed from the oral cavity and the barrier envelope is opened, the exposed imaging plate is removed from the barrier envelope in a light proof chamber for transport to a scanner to be digitally read with the imaging results stored in a central processing unit.
The patient must be protected against cross contamination and toxicity of the imaging plate wherein the imaging plate must be protected from saliva and other substances found in the patient""s mouth as well as protection from light until read. At present, barrier envelopes are generally rectangularly-shaped in various sizes to accommodate photo-stimulable phosphor imaging plates common to the dental arts, generally referred to as sizes 0 to 4. The rectangularly-shaped barrier envelope is formed of a plastic partially opaque film and a plastic transparent film sealed together about three sides defining a chamber for an imaging plate with an adhesively coated flap and cooperating flap about either a long or short dimension thereof with the adhesively coated flap formed with a peel-strip. A xe2x80x9cVxe2x80x9d notch is formed on one side or both flaps to facilitate tearing and removal of an exposed imaging plate. The imaging plate is inserted into the barrier envelope and the peel-strip removed to permit contact between the adhesive flap and cooperating flap and thus sealing of the imaging plate within the barrier envelope.
The xe2x80x9cVxe2x80x9d notch in a flap of the barrier envelope may have a finite radius at its point due to the manner in which the tooling is constructed, or due to wear of the tooling during manufacture of barrier envelopes. Such a finite radius decreases the ease with which the user can initiate a tear of the barrier envelope. Still further, since the barrier envelopes are constructed of plastic typically with orientation in one direction, the orientation is in a direction orthogonal to the normal direction of tear (as defined by the location of the notch) and therefore render such tearing and subsequent removal of the imaging plate more difficult. Difficulty in tearing makes removal of the imaging plate less controllable and thus requires more care in directing the ejected imaging plate into a receiving receptacle. The partially opaque plastic film is usually dark blue or navy blue in color and are thus of limiting shielding effect.
An object of the present invention is to provide an improved barrier envelope for an imaging plate which is easier to open.
A further object of the present invention is to provide an improved barrier envelope of improved light blocking capability.
These and other objects of the present invention are achieved by a barrier envelope for reusable photo-stimulable phosphor imaging plates, particularly for digital dental imaging comprised of a plastic transparent film and a plastic opaque film sealed to each other about three sides thereof defining a chamber for an imaging plate and wherein a free side of each film is formed with a flap and one flap is coated with an adhesive medium protected by a peel strip and wherein a xe2x80x9cYxe2x80x9d shaped notch is provided on a side of the barrier envelope adjacent to the free side of each film the barrier envelope to facilitate tearing open of the barrier envelope in a removal procedure and transport of an exposed imaging plate to an optical scanning assembly.